The present invention relates to longitudinal/horizontal magnetic recording apparatus, and more particularly, to an electromagnetic read/write head, or head structure, for the longitudinal/horizontal writing and reading of magnetic images with respect to a relatively moving magnetic recording medium, such as a magnetic recording disk.
In the prior-art world of longitudinal/horizontal magnetic recording, error problems have existed that result from the read/write head geometries which have been employed. More particularly, in prior-art heads, for example in thin-film heads, in addition to the two, linear, confronting, parallel pole edges which define the "operative" read/write gap, other edges in the pole components forming a head structure, even though somewhat remote from the operative gap edges, nevertheless parallel these gap edges, and are the distressing culprits. These remote but parallel other edges can, and do, exhibit what might be thought of as a "ghosting" behavior--the writing of unwanted, error-generating images on a medium, and the reading of normal images in a manner producing a false read-data stream.
A principal object of the present invention, in this setting, is to provide a revolutionary longitudinal/horizontal recording head-structure design having, to the best of my knowledge, no similarity to any prior-art head, and clearly having a geometric configuration which avoids the ghosting problems just mentioned.
Eliminating such other parallel edges is the focus, and the special accomplishment, of the head proposed by the present invention. Such elimination is achieved by a remarkable head pole-construction in which the only edges capable of creating (writing), and reading, longitudinally/horizontally oriented recorded images are the two edges that define a read/write gap in the head.
Outlining, in very broad terms, the unique geometric, and hence magnetic, characteristics of the proposed head, the same includes first and second magnetic pole components which are spaced by a substantially uniform-width linear planar gap. These pole components are each characterized by a configuration, measured generally in the "plane" of the gap, where no portion of the outline of a pole component, save that edge portion which define a side of the gap, includes any part which extends parallel to the gap-defining edge.
According to a preferred embodiment of the invention, the first pole component has a read/write face, lying in the plane just referred to, which face has a somewhat triangular outline, terminating at one end in a "point", and at the other end in a linear edge which defines one side of the read/write gap. The second pole component includes a read/write face lying in the same plane, which face terminates at one end in a linear edge that faces and substantially parallels the edge just mentioned in the first pole component, cooperating therewith to define the opposite side of the gap, with this second pole component's read/write face flaring away from the gap-defining edge with what might be thought of as a somewhat horn-like configuration. This "flaring-away" portion of the second pole component joins homogeneously with another portion which eventually shrinks in dimension to a "point".
This general outline of the proposed head of this invention, when read along with the detailed description and drawings forming part of this disclosure, describes a unique longitudinal/horizontal read/write electromagnetic head, wherein it is only in the region of the two, confronting, parallel, gap-defining edges that longitudinal (horizontal) reading and writing can occur. The problem of "ghosting", accordingly, is substantially completely eliminated.
Those skilled in the art will recognize, from the description which now follows, that many conventional materials and fabrication techniques, may be used to implement the head of the present invention. Certain materials, which I consider to be preferred, are described herein. Also, certain fabrication techniques, which I know to work well, are generally set forth. In connection with the latter, the reader may wish to review the disclosure found in my prior-issued U.S. Pat. No. 4,414,554, issued Nov. 8, 1983 for "Magnetic Imaging Apparatus". This patent, although specifically focused on a very different kind of read/write head, nevertheless discusses, in some detail, fabrication techniques which are useful in the handling of the specific materials which I discuss below as being employed preferably in the head which is the subject matter of this invention. Because of this, I am incorporating herein, by reference, the entirety of that patent's disclosure.
Achievement of the anti-ghosting objective outlined above, and various other features and advantages which distinguish and make special the head structure proposed by this invention, will become more fully apparent as the description which now follows is read in conjunction with the accompanying drawings.